title: Physicochemical decellularization of composite flexor tendon-bone interface grafts.
abstract: BACKGROUND
  Extremity injuries involving tendon attachment to bone are difficult to address. Clinically, tendon-bone interface allografts must be decellularized to reduce immunogenicity. Composite grafts are difficult to decellularize because chemical agents cannot reach cells between tissues. In this study, the authors attempted to optimize tendon-bone interface graft decellularization.
  
  
  METHODS
  Human flexor digitorum profundus tendons with attached distal phalanx were harvested from cadavers and divided into four groups. Group 1 (control) was untreated. Group 2 (chemical) was chemically treated with 5% peracetic acid, 0.1% ethylenediaminetetraacetic acid, and 0.1% sodium dodecyl sulfate. Group 3 (low-power) underwent targeted ultrasonication for 3 minutes (22,274 J, 126W) followed by chemical decellularization. Group 4 (high-power) underwent targeted ultrasonication for 10 minutes (88,490 J, 155W) followed by chemical decellularization. Decellularization was assessed histologically with hematoxylin and eosin stain and stains for major histocompatibility complex I stains. Cell counts were performed. The ultimate tensile load of decellularized grafts (group 4) were compared with pair-matched untreated grafts (group 1).
  
  
  RESULTS
  Average cell counts were 100 ± 41, 27 ± 10, 12 ± 11, and 6 ± 11 per high-power field for groups 1, 2, 3, and 4, respectively (p < 0.001). Decellularization using physical and chemical treatments (groups 3 and 4) resulted in substantial reduction of cells and major histocompatibility complex I molecules. There was no difference in ultimate tensile load between treated (group4) and untreated (group 1) samples (p > 0.5).
  
  
  CONCLUSIONS
  Physicochemical decellularization of tendon-bone interface grafts using targeted ultrasonication and chemical treatment resulted in near-complete reduction in cellularity and maintenance of tensile strength. In the future, these decellularized composite scaffolds may be used for reconstruction of tendon-bone injuries.
authors.affiliation: Stanford, Calif. From the Section of Plastic Surgery, VA Palo Alto Health Care System; and the Division of Plastic Surgery, Stanford University Medical Center.
authors.forename: Joel A
authors.initials: JA
authors.lastname: Bronstein
authors.forename: Colin Y L
authors.initials: CYL
authors.lastname: Woon
authors.forename: Simon
authors.initials: S
authors.lastname: Farnebo
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Behn
authors.forename: Taliah
authors.initials: T
authors.lastname: Schmitt
authors.forename: Hung
authors.initials: H
authors.lastname: Pham
authors.forename: Alesha B
authors.initials: AB
authors.lastname: Castillo
authors.forename: James
authors.initials: J
authors.lastname: Chang
mesh_terms: D001696:Biomechanical Phenomena; D016025:Bone Transplantation; D001842:Bone and Bones / Q000187:drug effects* / Q000503:physiopathology / Q000601:surgery; D002102:Cadaver; D005383:Finger Injuries / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D013710:Tendons / Q000187:drug effects* / Q000503:physiopathology / Q000637:transplantation; D013718:Tensile Strength; D014021:Tissue Preservation / Q000379:methods*; D014184:Transplantation, Homologous; D014465:Ultrasonics / Q000379:methods*